SyslogAppender: Method getSeverityForEvent() not called

[fenjen]

The class ch.qos.logback.core.net.SyslogAppenderBase defines

abstract public int getSeverityForEvent(Object eventObject);

This method is implemented by ch.qos.logback.classic.net.SyslogAppender and can be overridden. But it doesn't seem to serve any purpose as this method is never called. I think the severity is currently determined by

ch.qos.logback.classic.pattern.SyslogStartConverter.convert(ILoggingEvent)

which statically calls

int pri = facility + LevelToSyslogSeverity.convert(event);

Is this an oversight? What do I have to do to make getSeverityForEvent(Object) define the severity?